Hangzhou Lectures on Eigenfunctions of the Laplacian (am-188) (ebook)

Argumento de Hangzhou Lectures on Eigenfunctions of the Laplacian (am-188) (ebook)

Based on lectures given at Zhejiang University in Hangzhou, China, and Johns Hopkins University, this book introduces eigenfunctions on Riemannian manifolds. Christopher Sogge gives a proof of the sharp Weyl formula for the distribution of eigenvalues of Laplace-Beltrami operators, as well as an improved version of the Weyl formula, the Duistermaat-Guillemin theorem under natural assumptions on the geodesic flow. Sogge shows that there is quantum ergodicity of eigenfunctions if the geodesic flow is ergodic.

Sogge begins with a treatment of the Hadamard parametrix before proving the first main result, the sharp Weyl formula. He avoids the use of Tauberian estimates and instead relies on sup-norm estimates for eigenfunctions. The author also gives a rapid introduction to the stationary phase and the basics of the theory of pseudodifferential operators and microlocal analysis. These are used to prove the Duistermaat-Guillemin theorem. Turning to the related topic of quantum ergodicity, Sogge demonstrates that if the long-term geodesic flow is uniformly distributed, most eigenfunctions exhibit a similar behavior, in the sense that their mass becomes equidistributed as their frequencies go to infinity.

"The book is very well written. . . . I would definitely recommend it to anybody who wants to learn spectral geometry."--Leonid Friedlander, Mathematical Reviews0Preface ix
1A review: The Laplacian and the d'Alembertian 1
1.1 The Laplacian 1
1.2 Fundamental solutions of the d'Alembertian 6
2Geodesics and the Hadamard parametrix 16
2.1 Laplace-Beltrami operators 16
2.2 Some elliptic regularity estimates 20
2.3 Geodesics and normal coordinates|a brief review 24
2.4 The Hadamard parametrix 31
3The sharp Weyl formula 39
3.1 Eigenfunction expansions 39
3.2 Sup-norm estimates for eigenfunctions and spectral clusters 48
3.3 Spectral asymptotics: The sharp Weyl formula 53
3.4 Sharpness: Spherical harmonics 55
3.5 Improved results: The torus 58
3.6 Further improvements: Manifolds with nonpositive curvature 65
4Stationary phase and microlocal analysis 71
4.1 The method of stationary phase 71
4.2 Pseudodifferential operators 86
4.3 Propagation of singularities and Egorov's theorem 103
4.4 The Friedrichs quantization 111
5Improved spectral asymptotics and periodic geodesics 120
5.1 Periodic geodesics and trace regularity 120
5.2 Trace estimates 123
5.3 The Duistermaat-Guillemin theorem 132
5.4 Geodesic loops and improved sup-norm estimates 136
6Classical and quantum ergodicity 141
6.1 Classical ergodicity 141
6.2 Quantum ergodicity 153
Appendix 165
A.1 The Fourier transform and the spaces S(?ⁿ) and S'(?ⁿ)) 165
A.2 The spaces D'(?) and E'(?) 169
A.3 Homogeneous distributions 173
A.4 Pullbacks of distributions 176
A.5 Convolution of distributions 179
Notes 183
Bibliography 185
Index 191
Symbol Glossary 193